Final answer:
Compounds like 2,4-Dinitrophenol increase oxygen consumption and decrease ATP synthesis by uncoupling the proton gradient from ATP synthase, while Oligomycin decreases both by inhibiting ATP synthase.
Step-by-step explanation:
The question deals with the effects of certain compounds on the electron transport chain and ATP synthesis within mitochondria.
2,4-Dinitrophenol (DNP) acts as an uncoupler by transporting protons across the mitochondrial membrane, thereby bypassing ATP synthase, which results in an increase in oxygen consumption but a decrease in ATP synthesis.
This is because the energy from the proton gradient, which would normally be used to generate ATP, is instead released as heat.
In contrast, Oligomycin directly inhibits the ATP synthase (FF₁ATPase), leading to a decrease in both oxygen consumption and ATP synthesis because the electron transport chain is hindered by the inability to use the proton gradient to generate ATP.
When considering the options presented, the compound that matches the description of decreasing both oxygen consumption and ATP synthesis is Oligomycin.
If cyanide poisoning occurs, it inhibits cytochrome c oxidase, which is a crucial component of the electron transport chain.
This leads to a potential increase in the pH of the intermembrane space since protons are no longer being pumped into it.
Moreover, the inhibitory effect of cyanide on cytochrome c oxidase severely affects ATP synthesis, almost completely halting it because the necessary proton gradient cannot be maintained to drive ATP synthase.